Gearmotor with removable pinion

ABSTRACT

A gearmotor assembly wherein a pinion shaft has an interferencefit with the motor shaft and has an annular groove formed therein defining a shoulder for forcibly removing the pinion shaft from the motor shaft. The end of the motor shaft is received in an opening in the pinion shaft and has a reduced diameter pilot portion at the end thereof for providing and holding alignment of the motor and pinion shafts during assembly.

United States Patent 91 Allen 51 July 1,1975

[54] GEARMOTOR WITH REMOVABLE PINION 75 Inventor: Howard G. Allen, Roselle, NJ.

[73] Assignee: General Electric Company,

Schenectady, N.Y.

221 Fi1ed: Sept. 20, 1973 211 App1.No.: 399,263

[52 US. Cl 310/42; 310/83 [51] Int. Cl. H02k 15/00 [58 Field of Search 310/42, '75 R, 83

[56] References Cited 7 UNITED STATES PATENTS 1,734,500 11/1929 Rogers 310/83 X 2,130,111 9/1938 Whitney 310/83 UX 3,143,897 8/1964 Kohn 310/83 X Prirriary Examiiter-A. D. Peliinen Attorney, Agent, or F irm-Vale P. Myles [5 7] ABSTRACT A gearmotor assembly wherein a pinion shaft has an interference-fit With the motor shaft and has an annular groove forined therein defining a shoulder for forcibly removing the pinion shaft from the motor shaft. The end of the motor shaft is received in an opening in the pinion shaft and has a reduced diameter pilot portion at the end thereof for providing and holding alignment of the motor and pinion shafts during assembly.

4 Claims, 2 Drawing Figures GEARMOTOR WITH REMOVABLE PINION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention generally relates to gearmotors. and more particularly' to gearmotors having pinions and motor shafts that may be easily assembled together, and disassembled.

2. Description of the Prior Art A gearmotor conventionally comprises a motor having a gear box directly connected thereto. the motor shaft or an extension thereof extending into the gear box and having a pinion thereon forming a part of the gear train.

In one type of gearmotor. a separate pinion is connected to the motor shaft by means of an interference or press-fit. It may be desirable, either during manufacture of the gearmotor or during subsequent repair thereof. to remove the pinion from the motor shaft. However, such disassembly of the two shafts has been difficult to accomplish without damage to the motor shaft. pinion. or the rotor of the motor because of the press-fit. Further, precise alignment of the pinion and motor shaft is required in order to accomplish the press-fitting operation.

SUMMARY OF THE INVENTION It is accordingly an object of the present invention to provide an improved gearmotor assembly.

Another object of the invention is to provide an improved-gearmotor assembly having means facilitating disassembly of the press-fitted pinion and motor shafts. Still another object is to provide an improved gearmotor having means facilitating assembly of a pinion and motor shaft.

In one gearmotor assembly that embodies the invention in one form, there is included a motor having a stator assembly and a rotor assembly. The rotor assembly includes a shaft having first and second opposite extension portions. Bearing means support the rotor shaft for rotation. For example, a first end shield member is secured to the stator assembly and carries a first bearing which rotatably supports the first motor shaft extension portion. Power transmitting means are provided that include an input gear. As illustrated, this means includes apinion shaft having an end coaxially connected to the second motor shaft extension portion and also includes a pinion. The second motor shaft extension is provided with a reduced, pilot diameter portion that facilitates assembly with the pinion shaft. A second end shield member is secured to the stator member and carriesa second bearing rotatably supporting the pinion shaft intermediate the end thereof and the pinion. A gear box is provided that includes a housing mounted to the second end shield member. output gear means, and bearing means which may support an output shaft having a gear thereon. The pinion shaft extends into the housing with the pinion meshing with the output gear means. The end of the pinion shaft has an interferencefit with the second motor shaft extension portion, and the pinion shaft has abutment means formed thereon intermediate the second bearing and the pinion for removing the pinion shaft from the second motor shaft extension portion.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of one preferred embodiment of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view, partly in cross-section, showing an improved gearmotor embodying the invention; and

FIG. 2 is a cross-sectional view taken generally along the line 2 2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, the improved gearmotor, generally indicated at 10, comprises motor 12 with gear box 14 connected thereto as will shortly be described. Motor 12 is shown as being a conventional squirrel cage induction motor and comprises a rotor assembly that includes a rotor body 16 mounted on shaft 18 having extension portions 20, 22. Motor 12 could, of course, be a direct current or other type of motor, however, as will be understood. A stator assembly, including a core member 24 and field windings 26, is mounted in shell 28. End shield 30 abuts one endjof shell 28 and carries bearing 32 which rotatably supports extension portion 20 of rotor shaft 18. End shield, 34 abuts the other end of shell 28, end shields 30,34

being held in assembled relation by through-boltsf36.v Power transmitting means 38 includes a pinion and pinion shaft which has an inner end 40 with an'opening 42 therein which receives extension portion 22 of shaftv bearings 50, 52 which rotatably support output shaft 54 having its axis at right angles to the axis of rotor shaft 18 and the pinion shaft. The pinion shaftextends into housing 46 and has pinion 56 formed thereon meshing with gear 58 on output shaft 54. Seal 76, as will be un derstood, prevents ingress and egress of lubricant orother material to and from housing 46 along the input shaft.

During assembly of gearmotor 10, some damage or imperfection in one of the component parts may necessitate disassembly of the pinion from rotor shaft 18 in order to salvage the pinion or rotor and further, during subsequent repair of gearmotor 10, it may be desirable to disassemble the press-fit between the pinion and the rotor shaft. It is desirable that such disassembly be readily accomplished without damage to anyof the component parts of the gearmotor assembly'fi 'ln order' to accomplish disassembly of the press-fit between the Y pinion and rotor shafts, the pinion shaft has 'annul'a'r" groove 60 formed therein intermediate bearing 44 and pinion 56, groove 60 defining shoulder 62 which provides an abutment to facilitate forceful removal of the pinion from extension portion 22 of rotor shaft 18 with which there is an interference or press-fit.

Press-fitting of extension portion 22 of rotor shaft 18 with end 40 of the pinion shaft requires highly accurate alignment of the two parts. This press-fitting is facilitated, in accordance with one aspect of the invention, by the provision of a slightly reduced pilot-diameter portion 64 at the end of extension portion 22 of rotor shaft 18. Reduced pilot diameter 64 holds the pinion and rotor shafts in alignment as the parts are being pressed together and thus facilitates the assembly thereof.

In one actual reduction to practice of the invention, a gearmotor assembly having a power rating of one-half horsepower (intermittent duty) was constructed. A four-pole induction motor having an output speed of 1725 rpm was used. The output speed of the gearmotor assembly was 17 rpm and the output torque of the assembly was 400 inch-pounds.

The diameter of the rotor shaft (corresponding to region 70 of shaft 18) was 0.5000/0.4995 of an inch. The press-fit section of the shaft (corresponding to region 71 of shaft 18) had a diameter of 0.4928/0.4925 of an inch, and a nominal total axial length of 0.66 of an inch. The diameter of the pilot diameter section of this shaft (corresponding to section 64 in FIG. 1) was 0.4905/L4900 of an inch, and the nominal axial length thereof was 0.15 of an inch.

The pinion shaft of the reduced to practice assembly was formed to have an internal diameter 0.4915/0.49l0 of an inch, the nominal axial length of the bore therein was 0.70, of an inch. The nominal outer diameter of the pinion shaft (at the end 40 shown in FIG. 1) was 0.625 of an inch. The entrance of the shaft receiving bore of the pinion shaft was chamfered at'a 45 angle, e.g., as shown at 75 in FIG. 1.

l-n the construction just described, the rotor shaft was formedof cold drawn AISI C1 117 steel, while the pinion shaft and pinion was formed from AISI 4150 steel.

. The pull groove (see groove 60 in FIG. 1) on the pinion shaft in the assembly just referred to had a nominal diameter of 0.562 of an inch, while the shoulder defining enlarged. portion of the pinion shaft between the groove and pinion had a nominal diameter of 0.77 of an inch and nominal axial length of one-eighth of an inch.-

The foregoing specific description has been presented for purposes of exemplification only, and it will be understood that the invention may be used with gearmotors having larger or smaller power ratings. Also, changes may of course be made in the dimensions disclosed above while utilizing the invention.

While gearing of the type referred to as skew-axis gearing has been shown in FIGS. 1 and 2 (see, for example, Kobayashi U.S.Pat. No. 2,756,614; and Saari U.S. Pat. Nos. 2,696,125 and 2,731,886; the disclosures of all of which are incorporated herein by reference) gearmotors embodying the invention may be manufactured having worm, bevel, or any other desired type of gear members.

Accordingly, while there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

What l claim as new and desire to secure by Letters Patent oft he United States is:

l. Agearmotor assembly including a motor having a stator assembly and a rotor assembly including a shaft having first and second portions; bearing means rotatably supporting said rotor assembly; power transmitting means including an input gear coaxially connected with said shaft; a gear box having output gear means; said input gear meshing with said output gear means; said power transmitting means being assembled with said shaft, and being provided with abutment means adapted for use when removing said power transmitting means from said shaft; said power transmitting means includes a pinion and pinion shaft, and the abutment means comprises a shoulder of greater diameter than said pinion shaft.

2. The assembly of claim 1 wherein said power transmitting means is assembled with an interference-fit with said shaft; said shaft having a reduced-diameter pilot portion at the end thereof for facilitating coaxial alignment of said shaft and said power transmitting means.

3. A gearmotor assembly including a motor having a stator assembly and a rotor assembly including a shaft having first and second portions; bearing means rotatably supporting said rotor assembly; power transmitting means including an input gear coaxially connected with said shaft; a gear box having output gear means; said input gear meshing with said output gear means; said power transmitting means being assembled with said shaft with an interference-fit; said shaft having a reduced=diameter pilot portion at an end thereof for fa-. cilitating coaxial alignment of said shaft and said power transmitting means; said power transmitting means includes a pinion, pinion shaft, and abutment means adapted for use in removing the power transmitting means from the shaft of the rotor assembly; said abutment means comprising a shoulder adjacent to a groov in said pinion shaft.

4. A gearmotor assembly including a motor having a stator assembly and a rotor assembly including a shaft having first and second portions; bearing means rotatably supporting said rotor assembly; power transmitting means including an input gear coaxially connected with said shaft; a gear box having output gear means; said input gear and output gear means being of the skewaxis type with said input gear meshing with said output gear means; said power transmitting means being assembled with said shaft with an interference-fit; said shaft having a reduced-diameter pilot portion at an end thereof for facilitating coaxial alignment of said shaft and said power transmitting means; said power transmitting means includes a pinion and pinion shaft, said pinion shaft including a bore defining surface interferingly fitted to the shaft of the rotor assembly, and said pinion shaft having a reduced diameter groove with an immediately adjacent increased diameter shoulder, the increased diameter shoulder adapted for use when removing said power transmitting means from said shaft. l 

1. A gearmotor assembly including a motor having a stator assembly and a rotor assembly including a shaft having first and second portions; bearing means rotatably supporting said rotor assembly; power transmitting means including an input gear coaxially connected with said shaft; a gear box having output gear means; said input gear meshing with said output gear means; said power transmitting means being assembled with said shaft, and being provided with abutment means adapted for use when removing said power transmitting means from said shaft; said power transmitting means includes a pinion and pinion shaft, and the abutment means comprises a shoulder of greater diameter than said pinion shaft.
 2. The assembly of claim 1 wherein said power transmitting means is assembled with an interference-fit with said shaft; said shaft having a reduced-diameter pilot portion at the end thereof for facilitating coaxial alignment of said shaft and said power transmitting means.
 3. A gearmotor assembly including a motor having a stator assembly and a rotor assembly including a shaft having first and second portions; bearing means rotatably supporting said rotor assembly; power transmitting means including an input gear coaxially connected with said shaft; a gear box having output gear means; said input gear meshing with said output gear means; said power transmitting means being assembled with said shaft with an interference-fit; said shaft having a reduced-diameter pilot portion at an end thereof for facilitating coaxial alignment of said shaft and said power transmitting means; said power transmitting means includes a pinion, pinion shaft, and abutment means adapted for use in removing the power transmitting means from the shaft of the rotor assembly; said abutment means comprising a shoulder adjacent to a groove in said pinion shaft.
 4. A gearmotor assembly including a motor having a stator assembly and a rotor assembly including a shaft having first and second portions; bearing means rotatably supporting said rotor assembly; power transmitting means including an input gear coaxially connected with said shaft; a gear box having output gear means; said input gear and output gear means being of the skew-axis type with said input gear meshing with said output gear means; said power transmitting means being assembled with said shaft with an interference-fit; said shaft having a reduced-diameter pilot portion at an end thereof for facilitating coaxial alignment of said shaft and said power transmitting means; said power transmitting means includes a pinion and pinion shaft, said pinion shaft including a bore defining surface interferingly fitted to the shaft of the rotor assembly, and said pinion shaft having a reduced diameter groove with an immediately adjacent increased diameter shoulder, the increased diameter shoulder adapted for use when removing said power transmitting means from said shaft. 